C# ASP.NET MVC模型绑定

我的模型绑定有问题。如果我在CopyToModelStateDictionary方法中使用前缀，我不会得到无效控件的样式或验证消息。如果我不使用前缀，我会得到样式和验证消息，但是如果用户没有从动态创建的单选按钮列表中进行选择，页面就会崩溃。我怎样才能两者兼得？我不明白这里发生了什么

    [AcceptVerbs(HttpVerbs.Post)]
    public ActionResult Edit(int id, FormCollection collection)
    {
        Request request = requestRepository.GetById(id);
        UpdateModel(request);
        Helpers.CopyToModelStateDictionary(request.GetRuleViolations(), ModelState, "request");
        ...
        if (!ModelState.IsValid) 
        {
            return View("Edit_Requestor", request);
        }
    }

    public static void CopyToModelStateDictionary(NameValueCollection errors, ModelStateDictionary modelState, string prefix)
    {
        foreach (string key in errors)
        {
            foreach (string value in errors.GetValues(key))
            {
                modelState.AddModelError(prefix + "." + key, value);
            }
        }
    }

错误消息

Line 9:   foreach (ProblemType problemType in problemTypes)
Line 10:  {
Line 11:      Writer.Write(Html.RadioButton("ProblemType", problemType.Value));
Line 12:      Writer.Write(problemType.Text + "<br/>");
Line 13:  }

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谢谢你阅读我的问题

这可能会有所帮助

您正在添加一个模式错误，因此MVC正在尝试检索尝试的值，但由于您没有添加它，因此失败

---

这可能会有所帮助

您正在添加一个模式错误，因此MVC正在尝试检索尝试的值，但由于您没有添加它，因此失败

---

感谢您提供这些链接。我必须做更多的研究才能发布我的解决方案。这些链接非常有用。另外，如果有人需要更多帮助，请在StackOverflow中搜索“ValueProvider”。我将在进行更多测试后使用我的解决方案进行编辑。感谢这些链接。我必须做更多的研究才能发布我的解决方案。这些链接非常有用。此外，如果有人需要更多帮助，请在StackOverflow中搜索“ValueProvider”。我将在进行更多测试后使用我的解决方案进行编辑。

[NullReferenceException: Object reference not set to an instance of an object.]
System.Web.Mvc.HtmlHelper.GetModelStateValue(String key, Type destinationType) +63
System.Web.Mvc.Html.InputExtensions.InputHelper(HtmlHelper htmlHelper, InputType inputType, String name, Object value, Boolean useViewData, Boolean isChecked, Boolean setId, Boolean isExplicitValue, IDictionary`2 htmlAttributes) +328
System.Web.Mvc.Html.InputExtensions.RadioButton(HtmlHelper htmlHelper, String name, Object value, Boolean isChecked, IDictionary`2 htmlAttributes) +193
System.Web.Mvc.Html.InputExtensions.RadioButton(HtmlHelper htmlHelper, String name, Object value, IDictionary`2 htmlAttributes) +282
System.Web.Mvc.Html.InputExtensions.RadioButton(HtmlHelper htmlHelper, String name, Object value) +61
ASP.views_request_lstproblemtype_ascx.__Render__control1(HtmlTextWriter __w, Control parameterContainer) in c:\Web\Views\Request\lstProblemType.ascx:11
System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) +256
System.Web.UI.Control.RenderChildren(HtmlTextWriter writer) +19
System.Web.UI.Control.Render(HtmlTextWriter writer) +10
System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) +27
System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter) +99
System.Web.UI.Control.RenderControl(HtmlTextWriter writer) +25
System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) +134
System.Web.UI.Control.RenderChildren(HtmlTextWriter writer) +19
System.Web.UI.Page.Render(HtmlTextWriter writer) +29
System.Web.Mvc.ViewPage.Render(HtmlTextWriter writer) +59
System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) +27
System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter) +99
System.Web.UI.Control.RenderControl(HtmlTextWriter writer) +25
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1266